It is generally known to equip a motor vehicle with an alcohol and/or drug detector that interfaces with appropriate system(s) of the vehicle (such as the starter and/or ignition system) in order to prevent operation by a driver who is determined to be impaired by alcohol and/or other drugs in his/her body. Such a device/system is commonly referred to as a vehicle immobilizer or a starter interlock.
By way of example, EP 1 601 548 B1 discloses an immobilizer system for a motor vehicle having a key and a separate external analysis unit, where the vehicle can only be started with the key when the alcohol or drug content of the sample examined is below a pre-specified limit. This ensures that both the key is present and that the alcohol and/or drug test is negative.
DE 60 2004 013 379 T2 discloses a system for starting a car, where the system comprises a first key with which a door of the car can be opened and an ignition of the car can be operated, a second key and an immobilizer of the car, which immobilizer receives a message indicating the presence of the first key which has been inserted into the ignition, and which immobilizer prevents the car from being started before an OK signal has been received from the second key, where the alcohol level of a driver of the car is determined by the second key and an OK signal is transmitted from the second key to the immobilizer only when the alcohol level is below a pre-specified value, where the immobilizer allows operation of the ignition by means of the first key in the usual way when the second key has transmitted the OK signal.
DE 10 2007 047 709 A1 discloses a corresponding device in which, however, it is possible to bypass or decommission said device, for example in emergency situations. However, this is logged in order to prevent regular misuse.
However, there is still a demand for an immobilizer system which allows more flexible handling, for example which do not require an alcohol and/or drug test from everyone and do not take away all control from the driver, so that said driver is encouraged to use the system sensibly.